ncrack_input.cc

/***************************************************************************
 * ncrack_input.cc -- Functions for parsing input from Nmap. Support for   *
 * Nmap's -oX and -oN output formats.                                      *
 *                                                                         *
 ***********************IMPORTANT NMAP LICENSE TERMS************************
 *                                                                         *
 * The Nmap Security Scanner is (C) 1996-2019 Insecure.Com LLC ("The Nmap  *
 * Project"). Nmap is also a registered trademark of the Nmap Project.     *
 * This program is free software; you may redistribute and/or modify it    *
 * under the terms of the GNU General Public License as published by the   *
 * Free Software Foundation; Version 2 ("GPL"), BUT ONLY WITH ALL OF THE   *
 * CLARIFICATIONS AND EXCEPTIONS DESCRIBED HEREIN.  This guarantees your   *
 * right to use, modify, and redistribute this software under certain      *
 * conditions.  If you wish to embed Nmap technology into proprietary      *
 * software, we sell alternative licenses (contact sales@nmap.com).        *
 * Dozens of software vendors already license Nmap technology such as      *
 * host discovery, port scanning, OS detection, version detection, and     *
 * the Nmap Scripting Engine.                                              *
 *                                                                         *
 * Note that the GPL places important restrictions on "derivative works",  *
 * yet it does not provide a detailed definition of that term.  To avoid   *
 * misunderstandings, we interpret that term as broadly as copyright law   *
 * allows.  For example, we consider an application to constitute a        *
 * derivative work for the purpose of this license if it does any of the   *
 * following with any software or content covered by this license          *
 * ("Covered Software"):                                                   *
 *                                                                         *
 * o Integrates source code from Covered Software.                         *
 *                                                                         *
 * o Reads or includes copyrighted data files, such as Nmap's nmap-os-db   *
 * or nmap-service-probes.                                                 *
 *                                                                         *
 * o Is designed specifically to execute Covered Software and parse the    *
 * results (as opposed to typical shell or execution-menu apps, which will *
 * execute anything you tell them to).                                     *
 *                                                                         *
 * o Includes Covered Software in a proprietary executable installer.  The *
 * installers produced by InstallShield are an example of this.  Including *
 * Nmap with other software in compressed or archival form does not        *
 * trigger this provision, provided appropriate open source decompression  *
 * or de-archiving software is widely available for no charge.  For the    *
 * purposes of this license, an installer is considered to include Covered *
 * Software even if it actually retrieves a copy of Covered Software from  *
 * another source during runtime (such as by downloading it from the       *
 * Internet).                                                              *
 *                                                                         *
 * o Links (statically or dynamically) to a library which does any of the  *
 * above.                                                                  *
 *                                                                         *
 * o Executes a helper program, module, or script to do any of the above.  *
 *                                                                         *
 * This list is not exclusive, but is meant to clarify our interpretation  *
 * of derived works with some common examples.  Other people may interpret *
 * the plain GPL differently, so we consider this a special exception to   *
 * the GPL that we apply to Covered Software.  Works which meet any of     *
 * these conditions must conform to all of the terms of this license,      *
 * particularly including the GPL Section 3 requirements of providing      *
 * source code and allowing free redistribution of the work as a whole.    *
 *                                                                         *
 * As another special exception to the GPL terms, the Nmap Project grants  *
 * permission to link the code of this program with any version of the     *
 * OpenSSL library which is distributed under a license identical to that  *
 * listed in the included docs/licenses/OpenSSL.txt file, and distribute   *
 * linked combinations including the two.                                  *
 *                                                                         *
 * The Nmap Project has permission to redistribute Npcap, a packet         *
 * capturing driver and library for the Microsoft Windows platform.        *
 * Npcap is a separate work with it's own license rather than this Nmap    *
 * license.  Since the Npcap license does not permit redistribution        *
 * without special permission, our Nmap Windows binary packages which      *
 * contain Npcap may not be redistributed without special permission.      *
 *                                                                         *
 * Any redistribution of Covered Software, including any derived works,    *
 * must obey and carry forward all of the terms of this license, including *
 * obeying all GPL rules and restrictions.  For example, source code of    *
 * the whole work must be provided and free redistribution must be         *
 * allowed.  All GPL references to "this License", are to be treated as    *
 * including the terms and conditions of this license text as well.        *
 *                                                                         *
 * Because this license imposes special exceptions to the GPL, Covered     *
 * Work may not be combined (even as part of a larger work) with plain GPL *
 * software.  The terms, conditions, and exceptions of this license must   *
 * be included as well.  This license is incompatible with some other open *
 * source licenses as well.  In some cases we can relicense portions of    *
 * Nmap or grant special permissions to use it in other open source        *
 * software.  Please contact fyodor@nmap.org with any such requests.       *
 * Similarly, we don't incorporate incompatible open source software into  *
 * Covered Software without special permission from the copyright holders. *
 *                                                                         *
 * If you have any questions about the licensing restrictions on using     *
 * Nmap in other works, we are happy to help.  As mentioned above, we also *
 * offer an alternative license to integrate Nmap into proprietary         *
 * applications and appliances.  These contracts have been sold to dozens  *
 * of software vendors, and generally include a perpetual license as well  *
 * as providing support and updates.  They also fund the continued         *
 * development of Nmap.  Please email sales@nmap.com for further           *
 * information.                                                            *
 *                                                                         *
 * If you have received a written license agreement or contract for        *
 * Covered Software stating terms other than these, you may choose to use  *
 * and redistribute Covered Software under those terms instead of these.   *
 *                                                                         *
 * Source is provided to this software because we believe users have a     *
 * right to know exactly what a program is going to do before they run it. *
 * This also allows you to audit the software for security holes.          *
 *                                                                         *
 * Source code also allows you to port Nmap to new platforms, fix bugs,    *
 * and add new features.  You are highly encouraged to send your changes   *
 * to the dev@nmap.org mailing list for possible incorporation into the    *
 * main distribution.  By sending these changes to Fyodor or one of the    *
 * Insecure.Org development mailing lists, or checking them into the Nmap  *
 * source code repository, it is understood (unless you specify            *
 * otherwise) that you are offering the Nmap Project the unlimited,        *
 * non-exclusive right to reuse, modify, and relicense the code.  Nmap     *
 * will always be available Open Source, but this is important because     *
 * the inability to relicense code has caused devastating problems for     *
 * other Free Software projects (such as KDE and NASM).  We also           *
 * occasionally relicense the code to third parties as discussed above.    *
 * If you wish to specify special license conditions of your               *
 * contributions, just say so when you send them.                          *
 *                                                                         *
 * This program is distributed in the hope that it will be useful, but     *
 * WITHOUT ANY WARRANTY; without even the implied warranty of              *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the Nmap      *
 * license file for more details (it's in a COPYING file included with     *
 * Nmap, and also available from https://svn.nmap.org/nmap/COPYING)        *
 *                                                                         *
 ***************************************************************************/


#include "ncrack.h"
#include "utils.h"
#include "ncrack_input.h"
#include "services.h"


/*
 * Responsible for parsing an Nmap XML output file (with the -oX option).
 * Returns 0 for success and host_spec is set with a host-service specification
 * in the form <service_name>://<IP-address>:<port-number>.
 * Returns -1 upon failure - which is usually when the EOF is reached.
 * This function has to be called as many times as needed until it
 * returns -1 to signify the end of parsing.
 */
int
xml_input(FILE *inputfd, char *host_spec)
{
  static bool begin = true;
  int ch;
  char buf[4096];
  static char ip[16];
  char portnum[7];
  char service_name[64];
  char cpe[4];
  char *dynamic_service_name;

  /* check if file is indeed in Nmap's XML output format */
  if (begin) {

    /* First check if this is an XML file */
    if (!fgets(buf, 15, inputfd))
      fatal("-iX XML checking fgets failure!\n");
    if (strncmp(buf, "<?xml version=", 15))
      fatal("-iX file is not a XML file!\n");

    /* Now try to run the special string "nmaprun" to validate that this is
     * indeed a Nmap XML output file ------
     * This string doesn't appear in Zenmap's XML file, so I will remove
     * this check for now */
#if 0
    bool ok = false;
    memset(buf, 0, sizeof(buf));
    while ((ch = getc(inputfd)) != EOF) {
      if (ch == '\n') {
        if (!fgets(buf, 9, inputfd))
          fatal("-iX corrupted file: cannot find string \"<nmaprun\"\n");
        if (!strncmp(buf, "<nmaprun", 8)) {
          ok = true;
          break;
        }
      }
    }
    if (!ok)
      fatal("-iX file doesn't seem to be in Nmap's XML output format!\n");
#endif

    //memset(ip, '\0', sizeof(ip));
    begin = false;
  }

  memset(buf, 0, sizeof(buf));

  /* Ready to search for hosts and open ports */

  while ((ch = getc(inputfd)) != EOF) {
    if (ch == '<') {

      /* If you have already got an address from a previous invokation, then
       * search only for open ports, else go look for a new IP */
      if (!strncmp(ip, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", sizeof(ip))) {

        /* Search for string "address" */
        if (!fgets(buf, 7, inputfd))
          fatal("-iX <address> section searching fgets failure!\n");

        if (!strncmp(buf, "addres", 6)) {
          /* Now get the rest of the line which is in the following format:
           * <address addr="10.0.0.100" addrtype="ipv4" /> */
          unsigned int i = 0;
          while ((ch = getc(inputfd)) != EOF) {
            if (ch == '>')
              break;
            if (i < sizeof(buf) / sizeof(char) - 1)
              buf[i++] = (char) ch;
            else
              fatal("-iX possible buffer overflow!\n");
          }
          if (i < 12)
            fatal("-iX corrupted Nmap XML output file!\n");
          i--;
          char *addr = NULL;
          if (!(addr = memsearch(buf, "addr=", i)))
            fatal("-iX corrupted Nmap XML output file!\n");
          /* Now point to the actual address string */
          addr += sizeof("addr=");

          /* Now find where the IP ends by finding the ending double quote */
          i = 0;
          while (addr[i] != '"')
            i++;
          i++;
          if (i > sizeof(ip))
            i = sizeof(ip);
          Strncpy(ip, addr, i);

        } else if (!strncmp(buf, "runsta", 6)) {
          /* We reached the end, so that's all folks. Get out. */
          return -1;
        }

      } else {
        /* Search for open ports, since we already have an address */

        if (!fgets(buf, 7, inputfd))
          fatal("-iX <ports> section searching fgets failure!\n");

        if (!strncmp(buf, "ports>", 6)) {
          /* Now, depending on Nmap invokation we can have an extra section of
           * "extraports" which we ignore */
          if (!fgets(buf, 12, inputfd))
            fatal("-iX <extraports> section searching fgets failure!\n");
          if (!strncmp(buf, "<extraports", 11)) {
            /* Found "extraports" section. Now find the end of this section
             * Nmap ends "</extraports>" in a new line, so use that */
            while ((ch = getc(inputfd)) != EOF) {
              if (ch == '<') {
                if (!fgets(buf, 12, inputfd))
                  fatal("-iX extraports fgets failure!\n");
                if (!strncmp(buf, "/extraports", 11))
                  break;
              }
            }
          }
        }
        if (memsearch(buf, "port ", strlen(buf))) {
          /* We are inside a <port section */

          /* Now get the rest of the line which is in the following format:
           * <port protocol="tcp" portid="22"><state state="open"
           * reason="syn-ack" reason_ttl="0"/><service name="ssh"
           * method="table" conf="3" /></port>
           */
          memset(buf, 0, sizeof(buf));

          unsigned int port_section_length = 0;
          unsigned int subsection = 0;
          /* Since the <port section has a total of 3 subsections (port,
           * service, state) we can use that information for parsing */
          while ((ch = getc(inputfd)) != EOF) {

            int i = 0;
            if (ch == '>') {
              subsection++;
              if (subsection > 3)
                break;
            }

            /* Scanning with -A produces <cpe> sections at the end of the port
             * section in Nmap's XML output so if you find a cpe section,
             * go to next port
             */
            cpe[i++] = (char) ch;
            if (i == 3)
              i = 0;
            if (!strncmp(cpe, "cpe", 3)) {
              //printf("cpe\n");
              break;
            }

            if (port_section_length < sizeof(buf) / sizeof(char) - 1)
              buf[port_section_length++] = (char) ch;
            else
              fatal("-iX possible buffer overflow inside port parsing\n");
          }
          if (port_section_length < 40)
            fatal("-iX corrupted Nmap XML output file: too little length in "
                "<port> section\n");
          port_section_length--;

          char *p = NULL;
          if (!(p = memsearch(buf, "portid=", port_section_length)))
            fatal("-iX cannot find portid inside <port> section!\n");
          p += sizeof("portid=");

          /* Now find where the port number ends by finding the double quote */
          unsigned int i = 0;
          while (p[i] != '"')
            i++;
          i++;
          if (i > sizeof(portnum))
            i = sizeof(portnum);

          Strncpy(portnum, p, i);
          //printf("\nport: %s\n", portnum);

          /* Now make sure this port is in 'state=open' since we won't bother
           * grabbing ports that are not open. */
          p = NULL;
          if (!(p = memsearch(buf, "state=", port_section_length)))
            fatal("-iX cannot find state inside <port> section!\n");
          p += sizeof("state=");

          /* Port is open, so now grab the service name */
          if (!strncmp(p, "open", 4)) {

            p = NULL;
            if (!(p = memsearch(buf, "name", port_section_length))) {
                //fatal("-iX cannot find service 'name' inside <port> section!\n");

                /* No service name was found, so assume default association of port */
                dynamic_service_name = port2name(portnum);
                Snprintf(host_spec, 1024, "%s://%s:%s", dynamic_service_name, ip, portnum);
                if (dynamic_service_name)
                    free(dynamic_service_name);

                memset(ip, '\0', sizeof(ip));
                return 0;
            }
            p += sizeof("name=");

            i = 0;
            while (p[i] != '"')
              i++;
            i++;
            if (i > sizeof(service_name))
              i = sizeof(service_name);

            Strncpy(service_name, p, i);
            //printf("\nservice_name: %s\n", service_name);

            /* Now we get everything we need: IP, service name and port so
             * we can return them into host_spec
             */
            Snprintf(host_spec, 1024, "%s://%s:%s", service_name, ip, portnum);
            return 0;
          }

        } else if (!strncmp(buf, "/ports", 6)) {

          /* We reached the end of the <ports> section, so we now need a new
           * IP address - let the parser know that  */
          memset(ip, '\0', sizeof(ip));

        } else if (!strncmp(buf, "runsta", 6)) {
          /* We reached the end, so that's all folks. Get out. */
          return -1;
        }


      }

    }
  }

  return -1;
}


/*
 * Responsible for parsing an Nmap Normal output file (with the -oN option)
 * Returns 0 for success and host_spec is set with a host-service
 * specification in the form <service_name>://<IP-address>:<port-number>.
 * Returns -1 upon failure - which is usually when the EOF is reached.
 * This function has to be called as many times as needed until it 
 * returns -1 to signify the end of parsing. Each invokation will result in a
 * different host_spec being set.
 */
int
normal_input(FILE *inputfd, char *host_spec)
{
  static bool begin = true;
  int ch;
  char buf[256];
  static char ip[16];
  char portnum[7];
  char service_name[64];
  static bool port_parsing = false;
  static bool skip_over_newline = false;
  char tmp[256];
  size_t i = 0;

  /* check if file is indeed in Nmap's Normal output format */
  if (begin) {

    if (!fgets(buf, 7, inputfd))
      fatal("-iN checking fgets failure!\n");
    if (strncmp(buf, "# Nmap", 6) && strncmp(buf, "Fetchf", 6))
      fatal("-iN file doesn't seem to be a Nmap -oN file!\n");

    begin = false;
  }

  memset(buf, 0, sizeof(buf));
  memset(tmp, 0, sizeof(tmp));

  /* Ready to search for hosts and open ports */
  if (skip_over_newline) {
    skip_over_newline = false;
    goto start_over;
  }

  while ((ch = getc(inputfd)) != EOF) {

    /* copy each ch to tmp buffer for referencing later */
    if (i < sizeof(tmp))
      tmp[i++] = ch; 

    if (ch == '\n') {

start_over:
      /* Now get the open ports and services */
      if (!strncmp(tmp, "PORT", 4)) {
        port_parsing = true;
      } else {
        port_parsing = false;
      }
      i = 0; /* reset tmp */
      memset(tmp, 0, sizeof(tmp));


      /* If you have already got an address from a previous invokation, then
       * search only for open ports, else go look for a new IP */
      if (!strncmp(ip, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", sizeof(ip))) {

        /* Search for string "Nmap scan report" */
        if (!fgets(buf, 17, inputfd))
          fatal("-iN \"Nmap scan report\" section fgets failure!\n");

        if (memsearch(buf, "map scan report", 16)) {
          /* Now get the rest of the line which is in the following format:
           * 'Nmap scan report for scanme.nmap.org (64.13.134.52):'
           * OR
           * 'Nmap scan report for 10.0.0.100:'
           */

          unsigned int line_length = 0;
          while ((ch = getc(inputfd)) != EOF) {
            if (line_length < sizeof(buf) / sizeof(char) - 1)
              buf[line_length++] = (char) ch;
            else 
              fatal("-iN possible buffer overflow!\n");
            if (ch == '\n')
              break;
          }
          if (line_length < 10) 
            fatal("-iN corrupted Nmap -oN output file!\n");

          if (line_length < sizeof(buf) / sizeof(char) - 1)
            buf[line_length] = '\0';
          else 
            fatal("-iN possible buffer overflow!\n");

          char *addr = NULL;
          if (!(addr = memsearch(buf, "for", line_length)))
            fatal("-iX corrupted Nmap -oN output file!\n");
          /* Now point to the actual address string */
          addr += sizeof("for");

          /* Check if there is a hostname as well as an IP, in which case we
           * need to grab the IP only */
          unsigned int i = 0;
          char *p = NULL;
          if ((p = memsearch(buf, "(", line_length))) {
            addr = p + 1;

            while (addr[i] != ')')
              i++;
            i++;

          } else {

            while (addr[i] != '\n' && i < line_length)
              i++;
            i++;
          }

          if (i > sizeof(ip))
            i = sizeof(ip);
          Strncpy(ip, addr, i);

          //printf("ip: %s\n", ip);

        } else if (memsearch(buf, "map done", 16)) {
          /* We reached the end of the file, so get out. */
          return -1;
        }

      } else {


        if (port_parsing) {

          memset(buf, '\0', sizeof(buf));

          /* Now we need to get the port, so parse until you see a '/' which
           * signifies the end of the por-number and the beginning of the
           * protocol string (e.g tcp, udp) 
           */
          unsigned int port_length = 0;
          while ((ch = getc(inputfd)) != EOF) {
            /* If we get an alphanumeric character instead of a number,
             * then it means we are on the next host, since we were expecting
             * to see a port number. The alphanumeric character will usually
             * correspond to the beginning of the "Nmap scan report" line.
             */
            if (isalpha(ch)) {
              port_parsing = false;
              memset(ip, '\0', sizeof(ip));
              goto start_over;
            }
            if (ch == '/')
              break;
            if (port_length < sizeof(buf) / sizeof(char) - 1)
              buf[port_length++] = (char) ch;
            else 
              fatal("-iN possible buffer overflow!\n");

          }

          port_length++;
          if (port_length > sizeof(portnum) / sizeof(char))
            fatal("-iN port length invalid!\n");
          Strncpy(portnum, buf, port_length);

          //printf("port: %s\n", portnum);

          /* now parse the rest of the line */
          unsigned int line_length = 0;
          while ((ch = getc(inputfd)) != EOF) {
            if (ch == '\n') {
              skip_over_newline = true;
              break;
            }
            if (line_length < sizeof(buf) / sizeof(char) - 1)
              buf[line_length++] = (char) ch;
            else 
              fatal("-in possible buffer overflow while parsing port line.\n");
          }

          if (line_length > sizeof(buf) / sizeof(char) - 1)
            fatal("-iN port-line length too big!\n");
          buf[line_length] = '\0';

          /* Make sure port is open */
          char *p = NULL;
          if ((p = memsearch(buf, "open", line_length))) {

            p += sizeof("open");
            /* Now find the service name */
            unsigned int i = 0;
            while (p[i] == ' ' && i < line_length)
              i++;

            p += i;

            i = 0;
            while (p[i] != '\n' && p[i] != ' ')
              i++;
            i++;
            if (i > sizeof(service_name))
              i = sizeof(service_name);

            Strncpy(service_name, p, i);
            //printf("service_name: %s\n", service_name);

            /* Now we get everything we need: IP, service name and port so
             * we can return them into host_spec 
             */
            Snprintf(host_spec, 1024, "%s://%s:%s", service_name, ip, portnum);
            //printf("%s\n", host_spec);
            return 0;

          }

          goto start_over;

        }

      }

    }


  }

  return -1;

}